Use of chlorophyll solar cells

German scientists have found that a membrane protein called LHC-II is the most abundant in green plants and is considered to be a light-harvesting complex. This is a hollow spheroid with a typical positive pentahedral symmetry, which is filled with pigment molecules that absorb light energy and carry it.

These pigment molecules, including chlorophyll a (Chlorophylla), chlorophyll b (Chlorophyllb), carotenoids (Carotenoids) and so on. It is known that in the long evolutionary process, the plant only chooses chlorophyll a which absorbs red light and chlorophyll b which absorbs blue-violet light.

Recent studies have shown that, in response to low light conditions, some plants also derived from the absorption of long-wave light pigments. In 2010, the researchers accidentally extracted the chlorophyll from an algal bacterial colony in Shark Bay, Western Australia, and named it chlorophyll f. It can absorb red and infrared light, the wavelength range of 0.7 microns to 0.8 microns (infrared wavelength is 0.77 micron -1000 micron, divided into near infrared, mid-infrared).

From a chlorophyll-based light-harvesting system to a photoreaction center, together with 10 co-factors (eg, manganese, iron, magnesium, etc.), photosynthesis is a complex and delicate system that converts light into electricity, Into a fixed state of chemical energy, at one go.

Use of photosynthesis to make batteries

In recent years, scientists have begun to try to use the principle of photosynthesis development of the battery. For example, the plant chlorophyll extracted out into the artificial preparation of the film, the light will produce electricity. This is the chlorophyll battery.

In 2004, it was reported that American scientists have used spinach extracted protein to create a chlorophyll battery. They isolate proteins that can capture light from spinach and place them between two layers of conductive material. When there is light to the micro-device, the current is generated.

However, these protein molecules are very fragile, and when removed from the natural environment, they are often unable to continue working. So scientists mix them in a molecule called a peptide-like molecule called a peptide-based surfactant. These protective molecules form a protective film around these energy-producing proteins, just as they are in a plant environment.

The protein is placed on a thin gold plate, attached with a layer of conductive metal, the top layer is conductive organic material. When light shines on this "fake sandwich," the protein releases electrons and passes to the next layer of metal to form a current.

"We want to design processes that are as similar as possible to photosynthetic green leaves," says Professor Lewis of the California Institute of Technology, which focuses on solar energy development. "The idea is to achieve the function of collecting sunlight, Try to simplify.

In 2006, Professor Max Cruise of the University of Sydney, Australia, produced a synthetic chlorophyll molecule shaped like soccer, a highly branched bifurcated polymer made of carbon, hydrogen and nitrogen. Adhere to it is a synthetic pigment porphyrin (contributed to chlorophyll photosynthesis must not change the element, located in the center of magnesium ions). Using synthetic chlorophyll, Cruise and his research group to build an embryonic form of organic solar cells. It is hoped that eventually it will be possible to produce more efficient cells than existing solar cells. Because the green leaves can be effectively 30% -40% of the light energy into electricity.

"We already have a major component that mimics photovoltaic devices or solar cells, and in the long run we have to work out a way to make a simple application like a thin layer of paint on the roof," says Cruise. "He said the team also hopes to create a storage device, used to replace the metal-based battery.

In fact, the real chlorophyll solar cells, because "artificial green" difficult, is still in the research stage, but the principle of imitation photosynthesis of the battery has been manufactured, this is the dye-sensitized battery. Since 1991, the Swiss Lausanne Engineering (EPFL) M. Gratzel (Michael Granger) Professor led the research team in the technology breakthrough to 6 m 30w solar street light, Europe, America, Japan and other developed countries have been put into A lot of money R & D.

Shanghai University of Materials Science and Technology researcher Yang Weiguang said, dye-sensitized cells with sensitizer synthetic dye instead of chlorophyll in plants. At present, the British G24Innovations company already has 30 megawatts of production capacity, and production and sale of battery components products, conversion efficiency of 6% or more. Another Solaronix Switzerland, Israel 3Gsolar companies specializing in the production and sale of dye-sensitized solar cell materials such as dyes, slurries, electrolytes, electrode materials. Yang Weiguang said that the current maximum efficiency of dye-sensitized battery components up to 10%. This record is created by Japan's Sharp Corporation. "But only in the development stage, there is no commercial products."

The domestic dye-sensitized battery development and industrialization has also started. According to Yang Weiguang introduction, in addition to universities and research institutes, R & D, Rainbow Group Technology Center (Beijing) is currently the only dye-sensitized battery 12v inverter head enterprise R & D center. In the industry, in 2009, China Shipbuilding Heavy Industry state-owned Hanguang Machinery Factory (Handan) and the Chinese Academy of Sciences, a total investment of 150 million yuan of cooperation, the country's first "dye-sensitized solar cell" industrialization projects, but still no Products for sale. Another report said that on November 19, 2011, China's first new dye-sensitized solar cell project has been in Qingdao High-tech Zone Jiaozhou Bay North Park put into operation.